Previously machines having rotary cam systems associated with a cylinder and/or dial have had a creel for mounting yarn packages or bobbins rotatable conjointly with the cam systems. Drive is transmitted from a motor by a drive shaft to an annular gear associated with a lower cam system for a cylinder and hence by a backshaft to an annular gear associated with an upper cam system for a top cylinder or a dial. The creel was fastened rigidly to mounting members of the upper cam system. The dial itself can be shogged to a limited extent for setting up etc.
It is a requirement that body machines can be stopped quickly in the event of mal-function. Stopping may be initiated by an operator. Machines have also many so-called stop-motions to detect a mal-function and stop the machine automatically. Stop motions may detect needle damage or the running out of yarn. In either case it is important that the machine be stopped quickly to minimise needle damage and prevent the pressing-off of the fabric being knitted as a result of which knitting has to be started afresh. To assist quick stopping, the machine may have a brake to arrest the drive shaft and reduce overrunning of the cam systems after the drive has been disconnected or switched off. The cam systems may also have to be slowed or accelerated during knitting for certain operations.
The cam systems are designed to rotate in one direction. Rotation in a reverse direction is not possible and would lead to extensive needle damage.
The requirement for quick stopping of the machine to prevent serious knitting faults has in practice restricted the development of machines with rotary cam systems. If the number or size of yarn packages were to be increased or the number of feeds or knitting speeds to be increased above a certain level, momentum of the rotary masses would increase so that either the cam systems could not be halted sufficiently quickly or, if the brake were applied strongly, distortions in the drive system would occur by distortion of the drive or back shaft. This could be associated with a back lash after braking. As a result of back lash the cam systems move in reverse and occasion mechanical damage. The machine as a whole could also move on the supporting floor as a result of a sudden stop if the machine is not bolted down. More importantly as a result of the mechanism for oscillating the dial or a cylinder can be caused to move to and fro to a small extent within the freedom of movement necessary for the oscillating mechanism sufficiently to cause damage to the knitting instruments by interference between the two sets of needles. Also with double cylinder machines, one cylinder may overrun or turn back to a different extent than the other and damage any needles being transferred from cylinder to cylinder.
It is the object of the invention to provide a knitting machine with rotary cam systems which can be stopped or slowed down quickly and which can rotate at a high speed and/or carry more or bigger yarn packages and/or have more feeds.